If you're looking for a more tradition ska sound you're gonna wanna go with the specials or madness, they were older 2 Tone bands.

if you're looking for more early ska-punk or "third wave" as it's called your old standbys are gonna be the Mighty Mighty Bosstones, Reel Big fish (though I don't like them much), the Uptones, Aquabats, Goldfinger (though they are more punk in a lot of cases), Less than Jake, and one of my favorite bands Streetlight Manifesto, and along with them also Catch 22., Planet smashers are also a good mention, along with Mustard Plug, buck-o-nine.

If you're looking for more of like Speed punkska shit. Which I LOVE right now, look around for The Have Nots, The Flatliners, Arrogant Sons of Bitches (ASOB). I'm a lot more acquainted with a lot more Modern Ska/punk bands. But I will HIGHLY reccomend you check out the Flatliners. Absolutely fantastic band still making great music, along with streetlight manifesto.